Improve #4201 Visibility accessibility

[maryscar]

Description

Fixes 2 common accessibility issues with font color contrast in the Models property section that effect visual accessibility.

Motivation and Context

Fixes 2 common accessibility issues with font color contrast in the Models property section. Suggested updates to styling.
#4201

How Has This Been Tested?

Ran npm tests.
Accessibility testing was completed using internal tools as well as Google Accessibility Extension (https://chrome.google.com/webstore/detail/accessibility-developer-t/fpkknkljclfencbdbgkenhalefipecmb) and aXe Accessibility Engine (https://www.deque.com/products/axe/).

Screenshots (if appropriate):

Types of changes

• No code changes (changes to documentation, CI, metadata, etc)
• Dependency changes (any modification to dependencies in package.json)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[shockey]

Thanks, @maryscar!